A nickel positive electrode plate in accordance with the present invention includes a porous nickel substrate and an active material comprising a hydroxide of nickel filled into the substrate, the positive electrode plate having a layer of a manganese compound containing manganese with a valence of 2 or more on the surface thereof.
It is effective that the active material is a solid solution of a hydroxide of nickel containing at least one selected from the group consisting of cobalt, zinc, magnesium and manganese.
It is also effective that the active material has a hydroxide of cobalt on the surface thereof.
It is also effective that the layer of a manganese compound has a thickness of 0.1 to 20 μm.
Further, an alkaline storage battery in accordance with the present invention comprises: the above nickel positive electrode plate; a negative electrode plate; a separator; and an alkaline electrolyte.
Then, a method of producing a nickel positive electrode plate in accordance with the present invention comprises the steps of: (1) filling an active material comprising a hydroxide of nickel into a porous nickel substrate; and (2) forming a layer of a manganese compound on the surface of the substrate filled with an active material.
In this production method, it is effective that the step (2) is a step of forming a layer of a manganese compound on the surface of the substrate by charging and discharging the substrate filled with an active material at least once, and immersing the substrate in a saturated alkaline solution containing manganese ions.
Alternatively, it is effective that the step (2) is a step of forming a layer of a manganese compound on the surface of the substrate by immersing the substrate filled with an active material in a saturated alkaline solution containing manganese ions, while applying a potential to the substrate.
Alternatively, it is effective that the step (2) is a step of forming a layer of a manganese compound on the surface of the substrate by applying a manganese compound containing manganese with a valence of 2 or more onto the surface of the substrate filled with an active material, and immersing the substrate in a saturated alkaline solution containing manganese ions, while applying a potential to the substrate.
Further, a method of producing an alkaline storage battery in accordance with the present invention comprises the steps of: (1) causing any one of a positive electrode plate, a negative electrode plate and a separator to retain a powder of metallic manganese or a manganese compound containing manganese with a valence of 2 or more; (2) assembling a battery by using the positive electrode plate, the negative electrode plate, the separator and an alkaline electrolyte; and (3) charging and discharging a resultant battery at least once.
In this case, it is effective that the step (1) is a step of applying a manganese compound containing manganese with a valence of 2 or more onto the surface of the positive electrode plate.
Alternatively, it is effective that the step (1) is a step of applying a manganese compound containing manganese with a valence of 2 or more onto the surface of the separator.
Alternatively, it is effective that the step (1) is a step of applying a manganese compound containing manganese with a valence of 2 or more onto the surface of the negative electrode plate.
It is effective that said step (1) is a step of adding a powder of metallic manganese or a manganese compound containing manganese with a valence of 2 or more in the negative electrode plate.
Alternatively, it is effective that the step (1) comprises a step of forming manganese hydroxide in a pore of the separator by immersing the separator in an aqueous solution of a manganese salt, followed by immersing in an aqueous alkaline solution, and another step of drying a resultant separator containing manganese hydroxide in an inert atmosphere or under a reduced pressure.